Various types of garments and clothing utilize knit elastic tapes, particularly waistbands of the type used in the manufacture of men's and ladies' underwear, pantyhose and the like. The conventional type of knit elastic tape has a tendency to ravel along its exposed edge after the garment has been worn and laundered over a period of time because the yarn forming the stitch loop chains along the selvage edges become worn or broken. In order to prevent raveling of the stitch chain loops along the opposite selvage edges of the knit elastic tape, it has been proposed that additional yarns be incorporated in the selvage edge stitch loop chains to prevent raveling thereof.
Examples of the use of such additional yarns in the stitch loop chains along opposite selvage edges of the elastic tape are disclosed in U.S. Pat. Nos. 4,003,224; 4,009,597; and 4,248,064. However, the interknitting of the additional yarn in the outermost stitch loop chains, as disclosed in these patents, tends to add thickness to the opposite side edges of the elastic tape and can also change the stretchable characteristics of the outer edge portions of the elastic tape. More importantly, the addition of the locking yarn in the stitch loop chains along the selvage edges of the tape does not prevent raveling of the stitch loop chains extending throughout the medial portion of the elastic tape. While these medial stitch loop chains are not subjected to the wear that the outer stitch loop chains are subjected to, the medial stitch loop chains are also subject to raveling since the tape is usually transversely cut and attached either to itself and/or to the garment by a coursewise extending row of stitches and in some instances, the stitching causes or breaks the yarn forming the stitch loop chains so that they are free to ravel. Also, the coursewise row of stitches does not always sufficiently bond or bind the yarns forming the medial stitch loop chains so that they ravel.